JP2015220328A - Metal nitride material for thermistor, manufacturing method thereof, and film-type thermistor sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal nitride material for thermistors, which can be directly deposited on a film or the like and has high resistance and high B constant, a method for manufacturing metal nitride materials, and a film-type thermistor sensor.SOLUTION: The metal nitride material for thermistors comprises a metal nitride expressed by the following general formula: SiCr(NO)(where 0.70≤x/(x+y)≤0.98, 0.45≤z≤0.58, x+y+z=1, and 0<w<0.30). In X-ray photoelectron spectroscopy, spectra having a peak on an energy side, the Si peak of which is lower than that of SiN, are observed, however, in X-ray diffraction, a diffraction peak which enables the identification of a crystal phase is not observed, where B constant is 1700 to less than 6300 K. A method for manufacturing the metal nitride material for thermistors comprises a film growth step of depositing a film by using a Si vapor source and a Cr vapor source in an atmosphere containing nitrogen and oxygen by a reactive plasma vapor deposition method.

Description

  The present invention relates to a metal nitride material for a thermistor that can be directly formed on a film or the like, a manufacturing method thereof, and a film type thermistor sensor.

  A thermistor material used for a temperature sensor or the like is required to have a high B constant for high accuracy and high sensitivity. Conventionally, transition metal oxides such as Mn, Co, and Fe are generally used for such thermistor materials (see Patent Documents 1 to 3). In addition, these thermistor materials require heat treatment such as firing at 550 ° C. or higher in order to obtain stable thermistor characteristics.

In addition to the thermistor material composed of the metal oxide as described above, for example, in Patent Document 4, the general formula: M _x A _y N _z (where M is at least one of Ta, Nb, Cr, Ti, and Zr) , A represents at least one of Al, Si, and B. 0.1 ≦ x ≦ 0.8, 0 <y ≦ 0.6, 0.1 ≦ z ≦ 0.8, x + y + z = 1) A thermistor material made of nitride has been proposed. Moreover, in this patent document 4, it is Ta-Al-N type material, 0.5 <= x <= 0.8, 0.1 <= y <= 0.5, 0.2 <= z <= 0.7, x + y + z = 1. Only those described above are described as examples. This Ta—Al—N-based material is produced by performing sputtering in a nitrogen gas-containing atmosphere using a material containing the above elements as a target. Moreover, the obtained thin film is heat-processed at 350-600 degreeC as needed.

JP 2000-068110 A JP 2000-348903 A JP 2006-324520 A JP 2004-319737 A

The following problems remain in the conventional technology.
In recent years, development of a film type thermistor sensor in which a thermistor material is formed on a resin film has been studied, and development of a thermistor material that can be directly formed on a film is desired. That is, it is expected that a flexible thermistor sensor can be obtained by using a film. Furthermore, although development of a very thin thermistor sensor having a thickness of about 0.1 mm is desired, conventionally, a substrate material using ceramics such as alumina is often used. When thinned, there were problems such as being very brittle and fragile, but it is expected that a very thin thermistor sensor can be obtained by using a film.

  However, since a film made of a resin material generally has a heat resistant temperature as low as 150 ° C. or less, and polyimide known as a material having a relatively high heat resistant temperature has only a heat resistance of about 200 ° C., a thermistor material forming process In the case where heat treatment is applied, application is difficult. The conventional oxide thermistor material requires firing at 550 ° C. or higher in order to realize desired thermistor characteristics, and there is a problem that a film type thermistor sensor directly formed on a film cannot be realized. Therefore, it is desired to develop a thermistor material that can be directly formed on a film or the like, but even with the thermistor material described in Patent Document 4, the obtained thin film is obtained as necessary in order to obtain desired thermistor characteristics. It was necessary to perform heat treatment at 350 to 600 ° C. In this thermistor material, only examples of Ta-Al-N-based materials are described, and there is no example other than Ta-Al-N-based materials. The constant was unknown. In particular, even if a Si—N material is formed by reactive sputtering in the same manner as a Ta—Al—N material, it is considered that a dense film cannot be formed due to insufficient nitriding, and a high B constant is obtained. It is difficult.

  The present invention has been made in view of the above-mentioned problems, and can be directly formed on a film or the like, and has a high resistance and a high B constant, a metal nitride material for a thermistor, a manufacturing method thereof, and a film type thermistor. An object is to provide a sensor.

The inventors focused on the Si—N system among the nitride materials and made extensive research. As a result, Si ₃ N _{4 as} an insulator has optimum thermistor characteristics (B constant: about 1000 to 6000 K). However, it was found that a favorable B constant can be obtained without firing by replacing the Si site with a specific metal element that improves electrical conduction and a specific crystalline structure.
Therefore, the present invention has been obtained from the above findings, and the following configuration has been adopted in order to solve the above problems.

That is, the metal nitride material for a thermistor according to the first invention is a metal nitride material used in a thermistor, the general _{formula: Si x Cr y (N 1} -w O w) z (0.70 ≦ x /(X+y)≦0.98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0.30), and the peak of Si in X-ray photoelectron spectroscopy analysis with spectrum having a peak at a lower energy side than the Si ₃ N ₄ is observed, the diffraction peaks identifiable crystalline phases in X-ray diffraction is not observed, from the resistance values between 25 ° C. and 50 ° C. The obtained B constant is 1700K or more and less than 6300K.

This metal nitride material for a thermistor is a metal nitride material used for the thermistor, and has a general formula: Si _x Cr _y (N _1-w O _w ) _z (0.70 ≦ x / (x + y) ≦ 0. 98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0.30), and the peak of Si is lower than Si ₃ N ₄ in X-ray photoelectron spectroscopy A spectrum having a peak on the energy side is observed, and a diffraction peak capable of identifying a crystal phase is not observed in X-ray diffraction, and a B constant obtained from respective resistance values at 25 ° C. and 50 ° C. is 1700 K or more. Since it is less than 6300K, it can be used as a thermistor having a high resistance and a good high B constant.
This metal nitride material for thermistor has a spectrum in which the peak of Si has a peak on the energy side lower than Si ₃ N ₄ in X-ray photoelectron spectroscopy (XPS). That is, when the short-period structure and the bonding state between atoms are analyzed by XPS, the Si ₃ N ₄ crystal structure has the same crystal structure and bonding state as the Si ₃ N ₄ crystal structure, and the Si ₃ N ₄ crystal structure has the Si ₃ N ₄ crystal structure. It is confirmed that Ti enters the site and the peak of the spectrum is shifted to the lower energy side. In addition, since a diffraction peak capable of identifying a crystal phase is not observed in X-ray diffraction, when a long-period structure is analyzed by XRD, it does not have a specific long-period crystal structure and is amorphous. It can be seen that it has a structure. Thus, the metal nitride material for thermistors of the present invention is composed of a short-period crystal in which Ti is dissolved in a silicon nitride crystal, and the entire structure does not form a long-period crystal structure. It has a crystalline structure. In addition, when oxygen (O) is contained, the heat resistance is improved by an effect such as filling nitrogen defects in the crystal with oxygen or introducing interstitial oxygen.

When the above “x / (x + y)” (ie, Si / (Si + Cr)) is less than 0.70, the B constant becomes too small to be applied as a thermistor material.
Further, when the above “x / (x + y)” (that is, Si / (Si + Cr)) exceeds 0.98, the resistance value becomes too high and exhibits extremely high insulation, and thus cannot be applied as a thermistor material.
Further, if the “z” (that is, (N + O)) is less than 0.45, nitridation is insufficient, the resistance value and the B constant become too low, and cannot be applied as a thermistor material.
Further, when the above “z” (that is, (N + O)) exceeds 0.58, it cannot be produced by the following production method of the present invention. This is because the theoretical value of Si ₃ N ₄ when there is no defect at the nitrogen site is 4/7 (= 0.5714...), And nitrogen exceeding the theoretical value cannot be introduced. Even if all the defects at the site are compensated for by oxygen, this is because nitrogen and oxygen (that is, (N + O)) exceeding the theoretical value cannot be introduced. The z amount exceeding 4/7 is attributed to the introduction of light elements (nitrogen, oxygen) between the lattices and the quantitative accuracy of light elements (nitrogen, oxygen) in XPS analysis.
In addition, when the “w” (that is, O / (N + O)) is 0.3 or more, since the amount of oxygen with respect to the amount of nitrogen is too large, the resistivity is very high and the thermistor exhibits extremely high insulation. Not applicable as a material.

  The metal nitride material for a thermistor according to the second invention is characterized in that it is formed in a film shape in the first invention.

A film-type thermistor sensor according to a third aspect of the invention includes an insulating film, a thin film thermistor portion formed on the insulating film with the metal nitride material for the thermistor of the first or second aspect, and at least the thin film thermistor. And a pair of pattern electrodes formed above or below the portion.
That is, in this film type thermistor sensor, the thin film thermistor portion is formed of the metal nitride material for the thermistor of the first or second invention on the insulating film. The B constant thin film thermistor portion can use an insulating film with low heat resistance such as a resin film, and a thin and flexible thermistor sensor having good thermistor characteristics.
Conventionally, substrate materials using ceramics such as alumina are often used. For example, when the thickness is reduced to 0.1 mm, the substrate material is very brittle and easily broken. Therefore, for example, a very thin film type thermistor sensor having a thickness of 0.1 mm can be obtained.

A method for manufacturing a metal nitride material for a thermistor according to a fourth invention is a method for manufacturing a metal nitride material for a thermistor according to the first or second invention, wherein an Si evaporation source, a Cr evaporation source, It has the film-forming process which forms into a film by the reactive plasma vapor deposition method in nitrogen and oxygen containing atmosphere.
That is, in this method for producing a metal nitride material for the thermistor, a reactive plasma deposition (RPD) method is used in an atmosphere containing nitrogen and oxygen using an Si evaporation source and a Cr evaporation source. The film has a film forming process, so that it is sufficiently nitrided and Cr is dissolved in the crystal of silicon nitride, and the entire structure does not constitute a long-period crystal structure, but an amorphous structure The metal nitride material for thermistors of the present invention comprising the above-described SiCrNO having a thickness can be formed. In particular, this manufacturing method enables film formation at a low temperature of about room temperature.

The present invention has the following effects.
That is, according to the metal nitride material for a thermistor according to the present invention, the metal nitride material used for the thermistor has the general formula: Si _x Cr _y (N _1-w O _w ) _z (0.70 ≦ x /(X+y)≦0.98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0.30), and the peak of Si in X-ray photoelectron spectroscopy analysis A spectrum having a peak on the energy side lower than that of Si ₃ N ₄ is observed, and a diffraction peak capable of identifying a crystal phase is not observed in X-ray diffraction. From the respective resistance values at 25 ° C. and 50 ° C. Since the obtained B constant is 1700K or more and less than 6300K, it can be used as a thermistor having a high resistance and a good high B constant.
Further, according to the method for producing a metal nitride material for thermistor according to the present invention, reactive plasma deposition (RPD) is performed in an atmosphere containing nitrogen and oxygen using an evaporation source of Si and an evaporation source of Cr. ) Method, the metal nitride material for thermistor of the present invention made of SiCrNO can be formed.
Furthermore, according to the film type thermistor sensor according to the present invention, since the thin film thermistor portion is formed of the metal nitride material for thermistor of the present invention on the insulating film, the insulating film having low heat resistance such as a resin film. Can be used to obtain a thin and flexible thermistor sensor having good thermistor characteristics. Furthermore, since the substrate material is not a ceramic that is very brittle and fragile when thin, but a resin film, a very thin film type thermistor sensor having a thickness of 0.1 mm can be obtained.

1 is a Si—Cr— (N + O) -based ternary phase diagram showing a composition range of a thermistor metal nitride material in an embodiment of a thermistor metal nitride material, a method for manufacturing the thermistor metal film material, and a film type thermistor sensor according to the present invention. is there. In this embodiment, it is a perspective view which shows a film type thermistor sensor. In this embodiment, it is a perspective view which shows the manufacturing method of a film type thermistor sensor in order of a process. It is simple front sectional drawing which shows the internal structure of a reactive plasma vapor deposition (RPD) apparatus. In the Example of the metal nitride material for thermistors which concerns on this invention, its manufacturing method, and a film type thermistor sensor, it is the front view and top view which show the element | device for film | membrane evaluation of the metal nitride material for thermistors. In the Example which concerns on this invention, it is a graph which shows the profile of the spectrum of Si in X-ray photoelectron spectroscopy (XPS). In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between 25 degreeC resistivity and B constant. In the Example and comparative example which concern on this invention, it is a graph which shows the relationship between Si / (Si + Cr) ratio and B constant. In the Example which concerns on this invention, it is a graph which shows the result of X-ray diffraction (XRD). It is a cross-sectional SEM photograph of the Example which concerns on this invention.

  Hereinafter, an embodiment of a metal nitride material for a thermistor according to the present invention, a manufacturing method thereof, and a film type thermistor sensor will be described with reference to FIGS. In the drawings used for the following description, the scale is appropriately changed as necessary to make each part recognizable or easily recognizable.

The metal nitride material for a thermistor of this embodiment is a metal nitride material used for the thermistor, and has a general formula: Si _x Cr _y (N _1-w O _w ) _z (0.70 ≦ x / (x + y)) ≦ 0.98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0.30), and the peak of Si is Si ₃ N _{4 in} X-ray photoelectron spectroscopy. A spectrum having a peak on the lower energy side is observed, and a diffraction peak capable of identifying a crystal phase is not observed in X-ray diffraction, and the entire structure does not form a long-period crystal structure, and is amorphous. It has a qualitative structure, and the B constant determined from the respective resistance values at 25 ° C. and 50 ° C. is 1700K or more and less than 6300K.

As shown in FIG. 1, the metal nitride material for the thermistor has a composition in a region surrounded by points A, B, C, and D in the Si—Cr— (N + O) ternary phase diagram. Metal nitride.
The composition ratios (x, y, z) (atm%) of the points A, B, C, and D are A (16.50, 38.50, 45.00), B (1.10, 53). .90, 45.00), C (0.84, 41.16, 58.00), D (12.60, 29.40, 58.00).
The metal nitride material for thermistors of this embodiment is formed into a film by a manufacturing method described later.

  Next, a film type thermistor sensor using the metal nitride material for the thermistor of this embodiment will be described. As shown in FIG. 2, the film type thermistor sensor 1 includes an insulating film 2, a thin film thermistor section 3 formed on the insulating film 2 from the metal nitride material for the thermistor, and at least the thin film thermistor section 3. And a pair of pattern electrodes 4 formed thereon.

The insulating film 2 is formed in a band shape with, for example, a polyimide resin sheet. In addition, as the insulating film 2, PET: polyethylene terephthalate, PEN: polyethylene naphthalate, or the like may be used. Moreover, as the insulating film 2, the film which has 200 degreeC or more heat resistance, such as a polyimide, is suitable.
The pair of pattern electrodes 4 is formed by patterning a laminated metal film of, for example, a Cr film and an Au film, and a pair of comb-shaped electrode portions 4a having a comb-shaped pattern arranged on the thin film thermistor portion 3 so as to face each other, and these comb-shaped electrodes A tip end portion is connected to the portion 4a, and a base end portion is disposed on the end portion of the insulating film 2 and has a pair of linear extending portions 4b extending.

  On the base end portion of the pair of linearly extending portions 4b, a plating portion 4c such as Au plating is formed as a lead wire lead-out portion. One end of a lead wire is joined to the plating portion 4c with a solder material or the like. Further, the polyimide coverlay film 5 is pressure-bonded on the insulating film 2 except for the end of the insulating film 2 including the plated portion 4c. In place of the polyimide coverlay film 5, a polyimide or epoxy resin material layer may be formed on the insulating film 2 by printing.

  A manufacturing method of the metal nitride material for the thermistor and a manufacturing method of the film type thermistor sensor 1 using the same will be described below with reference to FIG.

  First, in the method of manufacturing a metal nitride material for a thermistor of this embodiment, a film is formed by a reactive plasma deposition (RPD) method in an atmosphere containing nitrogen and oxygen using an Si evaporation source and a Cr evaporation source. It has a film forming process. In the RPD method of this film forming process, nitrogen gas and oxygen gas are introduced into the apparatus as reaction gases, and Ar plasma is supplied from the plasma gun 11 to the Si evaporation source 12 and the Cr evaporation source 13 as shown in FIG. 14 is a physical vapor deposition method in which a thin film of a nitride film is deposited on a substrate (insulating film 2) placed on the top by melting, sublimating and ionizing 14. The RPD apparatus 10 used for this film formation is an ion plating apparatus using a pressure gradient type Ar plasma gun, which is equipped with two plasma guns 11 and deposits Si and Cr by independently controlling them. be able to.

More specifically, first, for example, the insulating film 2 of a polyimide film having a thickness of 50 μm shown in FIG. 3A is mounted on the substrate rotation support portion 15 in the RPD device 10. The substrate rotation support unit 15 is rotationally driven around the axis during film formation.
In FIG. 4, 16A is a crucible containing metal Si, 16B is a crucible containing metal Cr, and 17 is a reaction gas inlet.

Furthermore, while evacuating the inside of the device and keeping it in a vacuum,
-Furnace atmosphere temperature: room temperature
Evaporation source 12: metal Si
-Plasma gun discharge power for the evaporation source 12: 10 kW
Evaporation source 13: metallic Cr
-Plasma gun discharge power to the evaporation source 13: 5 to 9 kW
-Discharge gas flow rate: Argon (Ar) gas 80sccm
Reaction gas flow rate: nitrogen _{(N 2)} gas 50~100sccm
Oxygen (O ₂ ) gas 10-30 sccm
The metal for the thermistor is formed by vapor-depositing a composite nitride layer comprising a (Cr, Si) (N, O) layer having a predetermined composition and a target average layer thickness on the surface of the insulating film 2 A thin film thermistor portion 3 made of a nitride material is formed.
The thin film thermistor portion 3 is formed by forming a metal nitride material for the thermistor into a desired size using a metal mask.

  Next, by sputtering, for example, a Cr film is formed to 20 nm, and an Au film is further formed to 200 nm. Further, after applying a resist solution thereon with a bar coater, prebaking is performed at 110 ° C. for 1 minute 30 seconds, and after exposure with an exposure apparatus, unnecessary portions are removed with a developer, and post baking is performed at 150 ° C. for 5 minutes. Patterning is performed at. Thereafter, unnecessary electrode portions are wet-etched with a commercially available Au etchant and Cr etchant, and as shown in FIG. 3C, pattern electrodes 4 having desired comb-shaped electrode portions 4a are formed by resist stripping. . Alternatively, the pattern electrode 4 may be formed on the insulating film 2 first, and the thin film thermistor portion 3 may be formed on the comb electrode portion 4a. In this case, the comb electrode portion 4 a of the pattern electrode 4 is formed under the thin film thermistor portion 3.

  Next, as shown in FIG. 3 (d), for example, a polyimide coverlay film 5 with an adhesive having a thickness of 50 μm is placed on the insulating film 2 and pressed by a press at 150 ° C. and 2 MPa for 10 minutes. Adhere. Further, as shown in FIG. 3E, an end portion of the linearly extending portion 4b is formed with a 2 μm Au thin film by using, for example, an Au plating solution to form a plated portion 4c.

When a plurality of film type thermistor sensors 1 are manufactured simultaneously, after forming the plurality of thin film thermistor portions 3 and the pattern electrodes 4 on the large sheet of the insulating film 2 as described above, each film type thermistor sensor is formed from the large sheet. Cut to 1.
In this way, for example, a thin film thermistor sensor 1 having a size of 25 × 3.6 mm and a thickness of 0.1 mm is obtained.

Thus, in the metal nitride material for the thermistor of the present embodiment, the general formula: Si _x Cr _y (N _1-w O _w ) _z (0.70 ≦ x / (x + y) ≦ 0.98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0.30). In X-ray photoelectron spectroscopic analysis, Si has a peak on the energy side lower than Si ₃ N _4. In addition, a diffraction peak that can identify the crystal phase is not observed in X-ray diffraction, and the entire structure does not form a long-period crystal structure and has an amorphous structure. Since the B constant obtained from the respective resistance values at 25 ° C. and 50 ° C. is 1700 K or more and less than 6300 K, it can be used as a thermistor having a high resistance and a good high B constant. In addition, when oxygen (O) is contained, the heat resistance is improved by an effect such as filling nitrogen defects in the crystal with oxygen or introducing interstitial oxygen.

  Further, in the method for manufacturing a metal nitride material for the thermistor according to the present embodiment, a film forming step of forming a film by reactive plasma deposition in an atmosphere containing nitrogen and oxygen using an Si evaporation source and a Cr evaporation source. As a result, it is sufficiently nitrided and Cr is dissolved in the silicon nitride crystal, and the entire structure does not constitute a long-period crystal structure, but has an amorphous structure. The thermistor metal nitride material of the present invention comprising the above-mentioned SiCrNO can be formed. In particular, this manufacturing method enables film formation at a low temperature of about room temperature.

Therefore, in the film type thermistor sensor 1 using the thermistor metal nitride material of the present embodiment, the thin film thermistor portion 3 is formed on the insulating film 2 from the thermistor metal nitride material. A thin and flexible thermistor sensor having good thermistor characteristics can be used with the insulating film 2 having low heat resistance such as a resin film by the thin-film thermistor portion 3 having a high B constant, which can be formed in a thin film. can get.
Conventionally, substrate materials using ceramics such as alumina are often used. For example, when the thickness is reduced to 0.1 mm, there is a problem that the substrate material is very brittle and easily broken. In this embodiment, a film is used. Therefore, for example, a very thin film type thermistor sensor having a thickness of 0.1 mm can be obtained.

  Next, with respect to the metal nitride material for the thermistor according to the present invention, the manufacturing method thereof, and the film type thermistor sensor, the results of the evaluation made by the example manufactured based on the above embodiment will be specifically described with reference to FIGS. I will explain it.

<Production of film evaluation element>
As an example of the present invention and a comparative example, a film evaluation element 121 shown in FIG. 5 was produced as follows. In each of the following examples of the present invention, a thermistor metal nitride which was Si _x Cr _y (N _1-w O _w ) _z was produced.
First, a metal nitride material for a thermistor formed with various composition ratios shown in Table 1 having a thickness of 500 nm on a Si wafer with a thermal oxide film to be a Si substrate S with various composition ratios by the RPD method described above. The thin film thermistor part 3 was formed.

Next, a 20 nm Cr film was formed on the thin film thermistor portion 3 by sputtering, and a 200 nm Au film was further formed. Further, after applying a resist solution thereon with a spin coater, pre-baking is performed at 110 ° C. for 1 minute 30 seconds. After exposure with an exposure apparatus, unnecessary portions are removed with a developing solution, and post-baking is performed at 150 ° C. for 5 minutes. Then, patterning was performed. Thereafter, unnecessary electrode portions were wet-etched with a commercially available Au etchant and Cr etchant, and a patterned electrode 124 having a desired comb-shaped electrode portion 124a was formed by resist stripping. Then, this was diced into chips to obtain a film evaluation element 121 for B constant evaluation.
For comparison, comparative examples in which the composition ratio of Si _x Cr _y (N _1-w O _w ) _z is out of the scope of the present invention and the crystal system is different were similarly produced and evaluated.

<Evaluation of membrane>
(1) Composition analysis About the thin film thermistor part 3 formed into a film by the said RPD method, the elemental analysis was performed by the X ray photoelectron spectroscopy (XPS). In this XPS, quantitative analysis was performed on the sputtered surface having a depth of 20 nm from the outermost surface by Ar sputtering. The results are shown in Table 1. In addition, the composition ratio in the following table | surface is shown by "atomic%". Quantitative analysis was performed on a sputter surface having a depth of 100 nm from the outermost surface of some samples, and it was confirmed that the composition was the same as that of the sputter surface having a depth of 20 nm within the range of quantitative accuracy.

  In the X-ray photoelectron spectroscopy (XPS), the X-ray source is MgKα (350 W), the path energy is 58.5 eV, the measurement interval is 0.125 eV, the photoelectron extraction angle with respect to the sample surface is 45 deg, and the analysis area is about Quantitative analysis was performed under the condition of 800 μmφ. As for the quantitative accuracy, the quantitative accuracy of N / (Si + Cr + N + O) and O / (Si + Ti + N + O) is ± 2%, and the quantitative accuracy of Si / (Si + Cr) is ± 1%.

(2) Evaluation of Si binding energy by XPS Table 1 shows the results of acquiring the Si2p spectrum by XPS and measuring the Si binding energy from the peak position for the examples of the present invention. As an example, a profile of a spectrum by XPS in Example 3 of the present invention is shown in FIG. In addition to this example, the XPS spectra of bulk Si, Si ₃ N ₄ , and SiO ₂ are also shown by broken lines in FIG. 6 for comparison.

As a result of these X-ray photoelectron spectroscopic analyses, in each of the examples of the present invention, a spectrum in which the Si peak has a peak on the energy side lower than Si ₃ N ₄ is observed. That is, when the short-period structure and the bonding state between atoms are analyzed by XPS, the same crystal structure and bonding state as the Si ₃ N ₄ crystal structure are formed in a short period and the crystal structure of Si ₃ N ₄ The Cr peak shifts to the lower energy side due to Cr entering the Si site. Therefore, it can be seen that Cr is dissolved in the silicon nitride crystal.
It has also been confirmed that the peak of Cr2p is shifted to a higher energy side than Cr, and Cr does not exist as a single element, and Cr is dissolved in the silicon nitride crystal. I understand.

(3) Specific resistance measurement About the thin film thermistor part 3 formed into a film by the said RPD method, the specific resistance in 25 degreeC was measured by the 4 terminal method. The results are shown in Table 1.
(4) B constant measurement The resistance value of 25 degreeC and 50 degreeC of the element 121 for film | membrane evaluation was measured within the thermostat, and B constant was computed from the resistance value of 25 degreeC and 50 degreeC. The results are shown in Table 1. Further, it has been confirmed that the thermistor has a negative temperature characteristic from resistance values of 25 ° C. and 50 ° C.

In addition, the B constant calculation method in this invention is calculated | required by the following formula | equation from each resistance value of 25 degreeC and 50 degreeC as mentioned above.
B constant (K) = ln (R25 / R50) / (1 / T25-1 / T50)
R25 (Ω): resistance value at 25 ° C. R50 (Ω): resistance value at 50 ° C. T25 (K): 298.15K 25 ° C. is displayed as an absolute temperature T50 (K): 323.15K 50 ° C. is displayed as an absolute temperature

As can be seen from these results, the composition ratio of Si _x Cr _y (N _1-w O _w ) _z is within the region surrounded by points A, B, C, and D in the ternary triangular diagram shown in FIG. That is, in all the examples in the region where “0.70 ≦ x / (x + y) ≦ 0.98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0.30”, Thermistor characteristics of resistivity: 100 Ωcm or more and B constant: 1700 K or more are achieved.

FIG. 7 shows a graph showing the relationship between the resistivity at 25 ° C. and the B constant from the above results. A graph showing the relationship between the Si / (Si + Cr) ratio and the B constant is shown in FIG. From these graphs, a spectrum having a peak on the energy side lower than Si ₃ N _{4 in} the XPS analysis in the region of Si / (Si + Cr) = 0.7 to 0.98 is obtained at 25 ° C. A high resistance and high B constant region having a specific resistance value of 100 Ωcm or more and a B constant of 1700 K or more can be realized. In the data of FIG. 8, the B constant varies for the same Si / (Si + Cr) ratio. The amount of nitrogen and oxygen in the crystal are different, or the amount of lattice defects such as nitrogen defects and oxygen defects. This is because they are different.

  Comparative Example 3 shown in Table 1 is a region where N / (Si + Cr + N + O) is less than 45%, and the metal is in a crystalline state with insufficient nitriding. In this comparative example, it was found that both the B constant and the resistance value were very small and close to the metallic behavior. Comparative Examples 1 and 2 shown in Table 1 are regions where Si / (Si + Cr) <0.70, the specific resistance value at 25 ° C. is less than 100 Ωcm, the B constant is less than 1000 K, low resistance and low B It was a constant area.

(5) Thin film X-ray diffraction (identification of crystal phase)
The thin film thermistor portion 3 formed by the RPD method was analyzed by visual oblique angle X-ray diffraction (Grazing Incidence X-ray Diffraction) in order to identify the crystal phase.
This thin film X-ray diffraction was a small angle X-ray diffraction experiment, and was measured in the range of 2θ = 20 to 130 degrees with Cu as the tube, the incident angle as 1 degree.

  As a result of this analysis, as shown in FIG. 9 as an example of the XRD profile, a peak indicating a specific crystal phase other than the peak derived from the substrate (the peak indicated by (*) in FIG. 9) was not obtained. That is, when long-term analysis is performed by XRD, it can be seen that the examples of the present invention have an amorphous structure. As described above, the metal nitride material for thermistor of the present invention has a structure in which Cr is dissolved in a silicon nitride crystal in a short period analysis by XPS, but is amorphous in a long period analysis by XRD. Has a typical organizational structure.

(6) Evaluation of Crystal Form Next, as an example showing the crystal form in the cross section of the thin film thermistor section 3, the cross section SEM in the thin film thermistor section 3 of Example 3 formed on the Si substrate S with a thermal oxide film about 140 nm. A photograph is shown in FIG.
A sample obtained by cleaving and cleaving the Si substrate S is used as the sample of this example. Moreover, it is the photograph which observed the inclination at an angle of 45 degrees.
As can be seen from this photograph, examples of the present invention have a dense structure, but formation of columnar crystals or the like has not been observed.

  The technical scope of the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the spirit of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Film type thermistor sensor, 2 ... Insulating film, 3 ... Thin film thermistor part, 4,124 ... Pattern electrode

Claims (4)

A metal nitride material used for the thermistor,
General formula: Si _x Cr _y (N _1-w O _w ) _z (0.70 ≦ x / (x + y) ≦ 0.98, 0.45 ≦ z ≦ 0.58, x + y + z = 1, 0 <w <0 30).
In X-ray photoelectron spectroscopic analysis, a spectrum having a Si peak having a lower energy side than Si ₃ N ₄ is observed, and a diffraction peak capable of identifying a crystal phase is not observed in X-ray diffraction.
A metal nitride material for a thermistor, wherein a B constant obtained from respective resistance values at 25 ° C. and 50 ° C. is 1700 K or more and less than 6300 K. The thermistor metal nitride material according to claim 1,
A metal nitride material for a thermistor, characterized in that it is formed in a film shape. An insulating film;
A thin film thermistor portion formed of the metal nitride material for a thermistor according to claim 1 or 2 on the insulating film;
A film type thermistor sensor comprising at least a pair of pattern electrodes formed above or below the thin film thermistor section. A method for producing a metal nitride material for a thermistor according to claim 1 or 2,
A metal nitride material for a thermistor comprising a film forming step of forming a film by reactive plasma deposition in an atmosphere containing nitrogen and oxygen using an Si evaporation source and a Cr evaporation source Production method.